Add metrics for tracking UX impact of non-static CLD data providers

chrome/renderer/translate/translate_helper.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_RENDERER_TRANSLATE_TRANSLATE_HELPER_H_
 #define CHROME_RENDERER_TRANSLATE_TRANSLATE_HELPER_H_
 
 #include <string>
 
 #include "base/gtest_prod_util.h"
@@ skipping 95 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(TranslateHelperTest,
                            CLDDisagreeWithWrongLanguageCode);
   FRIEND_TEST_ALL_PREFIXES(TranslateHelperTest,
                            InvalidLanguageMetaTagProviding);
   FRIEND_TEST_ALL_PREFIXES(TranslateHelperTest, LanguageCodeTypoCorrection);
   FRIEND_TEST_ALL_PREFIXES(TranslateHelperTest, LanguageCodeSynonyms);
   FRIEND_TEST_ALL_PREFIXES(TranslateHelperTest, ResetInvalidLanguageCode);
   FRIEND_TEST_ALL_PREFIXES(TranslateHelperTest, SimilarLanguageCode);
   FRIEND_TEST_ALL_PREFIXES(TranslateHelperTest, WellKnownWrongConfiguration);
 
+  enum LanguageDetectionTiming {
+    ON_TIME,   // Language detection was performed as soon as it was requested
+    DEFERRED,  // Language detection couldn't be performed when it was requested
+    RESUMED,   // A deferred language detection attempt was completed later
+    kLanguageDetectionTimingMax  // bounding value for this enum

[Alexei Svitkine (slow), 2014/07/16 14:50:40]

Nit: Use same naming convention as for the other enum members.

[andrewhayden, 2014/07/17 08:36:19]

This is copied from the same place the rest of this approach came from, but I
have no qualms about changing it.

+  };
+
   // Converts language code to the one used in server supporting list.
   static void ConvertLanguageCodeSynonym(std::string* code);
 
   // Returns whether the page associated with |document| is a candidate for
   // translation.  Some pages can explictly specify (via a meta-tag) that they
   // should not be translated.
   static bool IsTranslationAllowed(blink::WebDocument* document);
 
   // RenderViewObserver implementation.
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
@@ skipping 34 matching lines @@
   void DeferPageCaptured(const int page_id, const base::string16& contents);
 
   // Start polling for CLD data.
   // Polling will automatically halt as soon as the renderer obtains a
   // reference to the data file.
   void SendCldDataRequest(const int delay_millis, const int next_delay_millis);
 
   // Callback triggered when CLD data becomes available.
   void OnCldDataAvailable();
 
+  // Record the timing of language detection, immediately sending an IPC-based

[jar (doing other things), 2014/07/16 16:44:44]

nit: perhaps better would be to aggregate these requests, so that you can rate
limit how often this fires.

For instance, you could rate limit by posting a delayed task, and having a bool
that indicates that there is already a task pending.

Without this, you'll be doing a lot of work (scanning all histograms in the
renderer!) each time you do a minor update in your histogram :-(.

It might even be interesting to put such functionality into the histogram system
itself, in case other folks want to fire such updates "RSN".

[andrewhayden, 2014/07/17 08:36:19]

Totally agree, but again very far out of scope for what should be a trivial
addition to the code here. I don't expect this to fire more than once per page
load in the VAST (>99%) majority of use cases.

+  // histogram delta update to the browser process in case the hosting renderer
+  // process terminates before the metrics would otherwise be transferred.
+  void RecordLanguageDetectionTiming(LanguageDetectionTiming);
+
   // An ever-increasing sequence number of the current page, used to match up
   // translation requests with responses.
   int page_seq_no_;
 
   // The states associated with the current translation.
   bool translation_pending_;
   std::string source_lang_;
   std::string target_lang_;
 
   // Time when a page langauge is determined. This is used to know a duration
@@ skipping 21 matching lines @@
   int deferred_page_seq_no_;
 
   // The contents of the page most recently reported to PageCaptured if
   // deferred_page_capture_ is true.
   base::string16 deferred_contents_;
 
   DISALLOW_COPY_AND_ASSIGN(TranslateHelper);
 };
 
 #endif  // CHROME_RENDERER_TRANSLATE_TRANSLATE_HELPER_H_